batch encrypting passwords

I have several users setup in a test environment...now they are about to
go into production and I need to change their password from cleartext to
crypt or something. Cna someone tell me how to encrypt all of them at
once? Using GQ for linux I can easily change password encrytpion, but
woudl like to do it all at once. Thanks,
--
Fernando Medina, Jr.
fmedina@grupo-uno.com
Grupo Financiero Uno